KR101189544B1

KR101189544B1 - DSSC having a Substrate with Surface having Micro-roughness

Info

Publication number: KR101189544B1
Application number: KR20100048004A
Authority: KR
Inventors: 김재상
Original assignee: 주식회사 세원
Priority date: 2010-05-24
Filing date: 2010-05-24
Publication date: 2012-10-11
Also published as: KR20110128513A

Abstract

The present invention relates to a new dye-sensitized solar cell with increased cell efficiency, and more particularly, a conductive thin film (transparent electrode) is formed on an inner surface of a transparent substrate and coated with nanoparticle oxides on which photosensitive dye molecules are adsorbed. In the dye-sensitized solar cell comprising a semiconductor electrode plate , a conductive thin film is formed on the inner surface of the substrate, and a counter electrode plate coated with nano metal, carbon, etc., the fine iron is formed on the substrate of the counter electrode plate It relates to a dye-sensitized solar cell characterized in that.
According to the present invention, the battery efficiency can be increased by adding a simple process compared with the related art by a complicated and sensitive repetitive process. In addition, battery efficiency can be increased without damaging durability.

Description

Dye-Sensitized Solar Cell with Micro-Iron on Substrate Surface {DSSC having a Substrate with Surface having Micro-roughness}

The present invention relates to a new dye-sensitized solar cell with increased battery efficiency, and more particularly, a dye-sensitized solar cell having a high battery efficiency by forming a fine unevenness on the inner surface or the outer surface of an electrode plate of a solar cell. It relates to a battery.

The depletion of fossil fuels and soaring prices, and rapid changes in global climate, call for sustainable energy acquisition technologies. Among them, solar energy is attracting the most attention for its infinite cleanliness and safety.

Conventionally, silicon type solar cells have been widely researched and used industrially, but the problem is that the cost is low and the economic efficiency is low. Recently, dye-sensitized solar cells (DSSCs) are being actively researched as next-generation solar cells that have energy conversion efficiency comparable to that of silicon solar cells and are inexpensive to produce. Dye-sensitized solar cells, unlike silicon solar cells, are photosensitive dye molecules capable of absorbing visible light to produce electron-hole pairs, and photoelectrochemical solar cells for transferring generated electrons.

The DSSC unit cell is a semiconductor electrode plate coated with a nanoparticle oxide (semiconductor layer) on which a photosensitive dye molecule is adsorbed on a conductive substrate, a counter electrode plate coated with nano metal, carbon, and the like on the conductive substrate, and the pair spaced uniformly. And an electrolyte layer between the electrode plates. In order to prevent leakage of the electrolyte filled between the pair of electrode plates and inflow of air or moisture from the outside, the inner space between the pair of electrode plates is completely sealed by a sealing band layer.

DSSC has the great advantage that it is possible to make transparent solar cell besides the low production cost compared to silicon solar cell, but it is hindering the industrialization because the cell efficiency is relatively lower than that of silicon based solar cell. Accordingly, efforts have been made to increase the efficiency of dye-sensitized solar cells in terms of material and structure.

As an attempt in the structural aspect of minimizing wasted (passed) sunlight by changing the structure of a solar cell, a method of forming a nanoparticle oxide layer into two layers as shown in FIG. 1A is known (Coordination Chemistry Reviews 248 (2004) 1381-138). That is, during fabrication of the semiconductor electrode plate, the TiO ₂ nanolayer having a 20 nm level is first formed and sintered, followed by laminating and sintering the TiO ₂ scattering layer having a 100-400 nm level. The solar cell semiconductor electrode plate is mounted in such a structure, the primary reflected / scattered from the second TiO ₂ layer the past light TiO ₂ layer, so that a portion of the light re-entering the first TiO ₂ layer, in which a battery efficiency increase It works. However, according to the related art, the manufacturing cost increases significantly as the process becomes very complicated, such as repeating the process of applying and sintering a TiO ₂ colloid solution to a substrate two or more times.

In another attempt to increase the efficiency by changing the structure of the solar cell, Korean Patent No. 10-0728194 discloses a method of roughening the surface of the semiconductor electrode, as shown in Figure 1b. According to this, as the contact area between the semiconductor electrode plate and the semiconductor layer increases, battery efficiency increases by about 14%. However, the solar cell fabricated by this method imparts fine roughness to the counter electrode plate of the present patent to improve efficiency by increasing the contact area of the semiconductor material (for example, TiO ₂ ) by forming the unevenness of the semiconductor electrode plate. There is a difference.

Korea Patent Registration 10-0728194

Coordination Chemistry Reviews 248 (2004) 1381-138

In the dye-sensitized solar cell, an object of the present invention is to provide a new type of dye-sensitized solar cell which exhibits excellent cell efficiency by forming a predetermined fine irregularity on the inner surface or the outer surface of the counter electrode plate substrate.

In order to achieve the above object, the present invention provides a conductive thin film formed on an inner surface of a transparent substrate and a nano electrode oxide coated with a nanoparticle oxide adsorbed thereon, a conductive thin film formed on an inner surface of a substrate. In the dye-sensitized solar cell comprising a counter electrode plate coated with nano-metal, carbon, etc. thereon, the present invention relates to a dye-sensitized solar cell in which fine irregularities are formed on a substrate of the counter electrode plate. In the present invention, a predetermined fine unevenness may be formed and used on a smooth substrate, or a substrate having a predetermined fine unevenness may be used in advance.

In the present invention, in order to obtain battery efficiency due to fine irregularities, an appropriate roughness of the substrate must be maintained. Therefore, in this invention, the roughness of the board | substrate by the said unevenness | corrugation is 5-100 micrometers, More preferably, it is 20-60 micrometers. If the roughness is outside this range, the effect of increasing battery efficiency is minimal.

In the present invention, the fine irregularities may be formed on the outer surface of the substrate of the counter electrode plate, or may be formed on the inner surface. When formed on the inner surface, it is preferable that the counter electrode plate unevenness is formed on the substrate before the conductive thin film is coated. That is, for example, after forming a predetermined fine irregularities on a raw substrate such as a glass substrate, the conductive thin film is coated, and then a counter electrode plate is manufactured by coating nano metal (for example, platinum), carbon, and the like. It is good.

In the present invention, the "inner surface" refers to the surface facing the overlapping semiconductor electrode plate and the counter electrode plate, and the "outer surface" refers to the surface exposed to the outside from the DSSC.

According to the present invention, the following effects can be obtained.

The battery efficiency can be increased by adding a simple process compared with the prior art by a complicated and sensitive repetitive process.

In addition, battery efficiency can be increased without damaging durability.

As a result, more economical DSSC can be provided.

1A and 1B are exemplary cross-sectional views of a dye-sensitized solar cell according to the prior art having a structure that minimizes wasted (passed) sunlight by changing the structure of the solar cell.
2A is a conceptual cross-sectional view of a dye-sensitized solar cell according to an embodiment of the present invention.
Figure 2b is a conceptual cross-sectional view of a dye-sensitized solar cell according to another embodiment of the present invention.
3 is a conceptual cross-sectional view of a dye-sensitized solar cell according to a comparative example.
Figure 4a is a photograph of the equipment used to form fine grains in an embodiment of the present invention.
Figure 4b is a conceptual diagram showing the operation of the equipment used to form fine irregularities in the embodiment of the present invention.
4C is an exemplary graph showing a cross section of a fine grain formed in an embodiment of the present invention.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings and embodiments. However, the accompanying drawings and embodiments are merely illustrative for easily describing the content and scope of the technical idea of the present invention, whereby the technical scope of the present invention is not limited or changed. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the technical idea of the present invention based on these examples.

In the drawing, the gap between the semiconductor electrode plate and the counter electrode plate and the particle size of the nanoparticle oxide to which the photosensitive dye molecules are adsorbed are exaggerated for the sake of understanding, and the fine iron on the inner or outer surface of the substrate is exaggerated. .

1A is a conceptual cross-sectional view of a dye-sensitized solar cell to which a glass substrate according to the prior art is applied, FIG. 1B is a representative view mentioned in the prior art patent, and FIGS. 2A and 2B are dye-sensitized solar cells according to an embodiment of the present invention. 3 is a conceptual cross-sectional view of a dye-sensitized solar cell according to a comparative example compared with the present invention. In the drawings, the distance between the two electrode plates is exaggerated for clarity.

As shown, in the DSSC according to the present invention, as the substrate of the counter electrode plate disposed on the rear surface opposite to the direction in which the sunlight is irradiated, an artificially formed predetermined roughness (roughness) may be used on a conventional glass substrate. (When formed on the inner surface or the outer surface), a glass, ceramic, synthetic resin or paper having a predetermined roughness (when formed on the inner surface) with roughness in the manufacturing process may be adopted as the substrate. When the fine surface is formed on the inner surface of the substrate, the conductive thin film and the nano metal or carbon layer is coated on the substrate with fine irregularities and used as the counter electrode plate. In the drawings, the grooves are exaggerated to express the roughness of the surface. FIG. 2A illustrates an embodiment in which fine irregularities are formed on an outer surface of a transparent counter electrode plate substrate, and FIG. 2B illustrates fine irregularities in an inner surface of a (transparent or opaque) counter electrode substrate, on which a conductive thin film and a nanometal or carbon layer are formed. Coated Example.

< Example >

1. Fabrication of counter electrode plate and solar cell according to the present invention

The surface of the glass substrate used in the DSSC is usually formed a predetermined fine irregularities to the outer surface of the counter electrode plate (Comparative Example 1, Examples 1 to 5), or a predetermined fine irregularities are formed on the surface of the glass substrate and the conductive thin film And coating a nano metal or a carbon layer to form an inner surface of the counter electrode plate (Examples 6 to 10), or a conductive thin film on a substrate of various materials (ceramic plate, paper, acrylic, etc.) in which predetermined fine irregularities are formed in advance. Coating the nano metal or carbon layer to the inner surface of the counter electrode plate (Examples 11 to 19) or coating the conductive thin film and the nano metal or carbon layer on the glass substrate, and then forming a predetermined fine roughness to the inner surface of the counter electrode plate. (Comparative Examples 2 to 6) to produce a DSSC cell.

Glass substrates with fine irregularities formed on the surface may be produced by ordering from a conventional substrate manufacturer, or may be obtained by treating a conventional substrate by various methods.

In the following example, micro-blaster (Sechang Machinery Co., Ltd.) was used to form fine roughness of various roughness on the surface of the glass substrate, and then washed to prepare a DSSC (see FIGS. 4A and 4B).

The operating conditions of the Micro-Blaster were as shown in Table 1 below. However, it is obvious that a variety of micro irregularities can be formed under various conditions.

The roughness of the fine grains formed on the processed glass substrate surface was measured by Alpha-Step IQ (KLA-Tencor, USA), or SJ-301 (Miltutoyo, Japan). An example of the measured roughness is shown in FIG. 4C.

As shown in Tables 2 to 4, an ITO-Pt coating layer was formed on the raw substrate for the counter electrode having a predetermined material and fine roughness by a conventional method, thereby preparing the counter electrode plate.

Using the counter electrode plate thus manufactured, a conventional DSSC cell consisting of components shown in Table 5 below was manufactured.

2. Comparative Analysis of Battery Efficiency of Solar Cell

The solar cells thus produced were shown in Tables 6 to 8 by comparing and measuring battery characteristics and efficiency under the conditions of AM1.5.

As can be seen from the above table, ① When the surface of the counter electrode plate made of glass 5 ~ 100um roughness, the efficiency is increased by about 1 ~ 14% or more compared to the DSSC according to the prior art (Comparative Example 1), ② glass material When 5 ~ 100um of roughness was formed on the inner surface of the counter electrode plate and transparent electrode and Pt film were formed, the efficiency was increased by about 6 ~ 17% or more compared to DSSC according to the conventional technique (Comparative Example 1). When the transparent electrode and the Pt film were formed on the surface of ceramic, paper, and acrylic having a roughness of 5 to 100 μm, the efficiency was increased by about 4 to 13% or more compared to the DSSC according to the prior art (Comparative Example 1).

On the other hand, it can be inferred to those skilled in the art from the above test that similar results may be obtained even if the ceramic, paper or acrylic of different properties, and even other kinds of synthetic resins or paper and synthetic resin composites are applied to the present invention.

Although the cause of the increase in battery efficiency due to the roughness of the outer and inner surfaces of the counter electrode has not been identified, the light passing through the semiconductor electrode plate and the TiO ₂ layer is reflected / scattered from the inner surface of the counter electrode plate having the rough surface. Since light flows back into the TiO ₂ layer, it is assumed that the battery efficiency is increased.

10: semiconductor electrode plate
11. Substrate 12. Conductive Film 13. TiO ₂ Nano Layer 14. TiO ₂ Scattering Layer
20: counter electrode plate
21. Substrate 22. Conductive Film 23. Pt Film
R: Fine iron

Claims

It includes a semiconductor electrode plate coated with a nanoparticle oxide on which a photosensitive dye molecule is adsorbed on a conductive thin film (transparent electrode) formed on the inner surface of the transparent substrate, a counter electrode plate coated with nano metal, carbon, etc. on the conductive thin film formed on the inner surface of the substrate In dye-sensitized solar cell,
Dye-sensitized solar cell, characterized in that fine roughness is formed on the outer surface or the inner surface of the substrate of the counter electrode plate so that the roughness of the substrate is 5 ~ 100㎛.

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The method of claim 1,
Dye-sensitized solar cell, characterized in that the roughness of the substrate by the fine roughness is 20 ~ 60㎛.

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